/*
 * Copyright (c) 2018 Spotify AB.
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package com.spotify.heroic.http.tracing;

import io.opencensus.trace.propagation.TextFormat;
import java.util.List;
import javax.annotation.Nullable;
import org.glassfish.jersey.server.ContainerRequest;

public class TextFormatGetter <C> extends TextFormat.Getter {

  @Nullable
  @Override
  public String get(final Object o, final String s) {

    final ContainerRequest request = (ContainerRequest) o;
    final List<String> requestHeader = request.getRequestHeader(s);

    if (requestHeader != null && requestHeader.size() > 0) {
      return requestHeader.get(0);
    }

    return null;
  }
}
